[Lancaster] Firewall problem

[andy baxter]

Hi ken,

As far as I know windows will use the same two ports - 20 and 21. Are 
you sure the problem is with the firewall? I haven't followed your 
description of the problem that well, but another possibility might be 
that the ftp client you're using uses an ftp mode that your server 
doesn't like. There are quite a few different options for how an ftp 
transfer is set up, including the active/passive thing I said about, so 
maybe you just need to use a different client on the windows box, or 
configure it or the server differently?

One thing you could try if you're desperate is to install a packet 
logger (does wireshark work in windows?) and use that to see what's 
going on when you try to connect.

andy

Ken Hough wrote:
> Andy,
>
> Thanks for your suggestion.
>
> I've just tried using the simple terminal ftp client that's included with 
> Windows XP and this works OK with firewalls active on both my laptop and my 
> Linux box.
>
> So it looks like the basic vsftp setup is OK.
>
> The problem occurs when I try to use 'windows' to do the job. ie either 
> via "My Computer" and "My Network Places", or via Firefox. Both of these work 
> if I disable the firewall on my Linux box, so it seems that for 'windows' 
> operation, (an)other port/ports is/are used.
>
> Has anyone any suggestions as to what this/these might be?
>
> The reason that I want to sort this out is because:
>
> 1. I like to get things working. ;-)
>
> 2. I need to use XP to run Windows only software on my laptop to control a 
> motor driven equatorial mount and my astro camera(s), but I intend to 
> process/manage the captured images on my desktop PC under running Linux.
>
> 3. There can be a lot of Image files, each of several MB up to possibly 
> hundreds of MB, so fiddling with USB memory sticks is a pain. Much better to 
> transfer via ftp/ethernet.
>
> 4. I did have a look at setting up a SAMBA server, but for Windows XP this 
> seems to be a lot more complicated than for ftp.
>
> Regards
>
> Ken Hough
>
>
> On Friday 18 September 2009 18:34:31 you wrote:
>   
>> Ken Hough wrote:
>>     
>>> Hi Guys,
>>>
>>> Can anyone help me with a firewall problem.
>>>
>>> I'm trying use my T42 Thinkpad to access an ftp server that is running on
>>> my desktop PC. The T42 runs Windows XP (yes, I know, but I need it to run
>>> some astro software). The desktop PC runs openSUSE v11.1.
>>>
>>> I'm using vsftp which is clearly configured OK and can be accessed from
>>> the T42, provided that I turn off the firewall on the Linux machine.
>>>
>>> OpenSUSE includes a nifty utility for setting up the firewall, but
>>> doesn't seem to be setting up correctly to allow for vsftp.
>>>
>>> Can someone please tell me what ports must be left open for vsftp
>>> operation?
>>>
>>> According to the firewall utility, for vsftp, port 20 should be open.
>>> According to lists of recognised TCPIP ports, 21 should also be open, and
>>> I've tried this but with no success.
>>>       
>> The only thing I know about this is there are two different FTP modes
>> (Passive and active). One uses both ports, using 21 for setting up the
>> transfer and 20 for moving data, whereas the other uses only one port
>> (21 I think). Some ftp clients let you choose which mode to use.
>>
>> I.e. you definitely want both ports open, but it sounds like you've
>> already tried that.
>>
>> You could try doing 'telnet <ftp host name> 21' from the client machine,
>> and see what response you get with the firewall up and down. This might
>> give you a clearer idea of whether the firewall is configured right. (If
>> it is, the response should be the same in both cases)
>>
>> andy
>>     
>
>
>
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